Dead Link Removed. 'Nuff said. (you can maybe give it to others like Kodak on Hutt St, but they'll just post it to Atkins anyway)
Black and Whites in Payneham also do E6, or at least they did a year or two ago when I switched to Atkins.
Atkins do everything including 4x5 and 8x10 which is primarily why I switched to them, even though they're a bit pricier the quality is better (although mostly I do my own since I got the Jobo, I'm driving there this arvo to put one in).
Seeing as you look like you're from Melbs, I'll give some easy directions:
Start from Victoria Square (centre of the city). Go East down Wakefield Street, through the parklands, to the big ugly double-roundabout. If you survive making it across, take the first left around behind the buildings (ie don't go left alongside the parklands), and it's about 50m down, you should see their sign from the roundabout.